There is a need for quality control in the field of broadcasting in order to ensure that the composite video signal is maintained without distortion throughout the video system. To this end, various test signals have been developed to test the quality of the video system. One of the more widely used test signals is the multifrequency burst, hereinafter referred to as multiburst.
The multiburst test signal is produced by a multiburst generator. This generator produces a series of equal-amplitude bursts or packets of sine waves from 0.5 MHz to 4.2 MHz (NTSC television system) or from 0.5 MHz to 5.8 MHz (PAL television system) and white and black reference levels. The output also contains composite sync so that the complete signal will pass in the normal manner through various television equipment and circuits. Multiburst is generally used for a quick check of gain versus frequency response. The signal is passed through the video equipment and monitored on an oscilloscope. The video equipment's response to the various frequency bursts is apparent by their relative amplitudes.
This multiburst signal is usually generated by successively switching a function generator or a series of oscillators on for a short time. However, the high-speed switching circuitry used produces undesirable harmonic-frequencies or sidebands that may interfere with other video equipment.